362 Zoological Classification. 



ZOOLOGICAL CLASSIFICATION* 



The progress of comparative anatomy and physiology has re- 

 sulted from two circumstances : first, the number and variety 

 of creatures that have been carefully examined, is enormously 

 larger than it was a few years ago ; and secondly, the examina- 

 tion has, in many instances, been more accurate and profound. 

 At an early period of the study of fossils, the points of resem- 

 blance between extinct and living forms could not fail to be 

 noticed, and the first triumphs of scientific interpreters in this 

 department were won through the application of empirical 

 laws, resting upon a very limited range of known facts^ in 

 accordance with which it was assumed that if any one charac- 

 ter could be distinctly determined, a clue was afforded to the 

 whole nature and structure of the creature under considera- 

 tion. No one, except upon the ground of an obvious or 

 fancied convenience, pretended to know why a particular 

 form of hoof, tooth, or horn was found associated with 

 special peculiarities of the skeleton, a definite structure of 

 limbs, a certain kind of covering super-imposed upon the true 

 skin, or the adaptation of digestive organs to particular kinds 

 of food ; but certain characteristics were found to be asso- 

 ciated in all known cases, and hence, though without adequate 

 reason, a strict and never deviating uniformity of rule was in- 

 ferred. There can be no doubt that many observers have 

 greatly over-estimated the probability of rules or laws of an 

 empirical kind proving to be universal and invariable, and it 

 has also been customary to push the doctrine, that structure 

 and special utility always go hand in hand, much too far. More 

 complete research has thrown discredit upon the assumption 

 that the rule we see observed in many cases is necessarily 

 maintained in all cases ; and no anatomist of competent infor- 

 mation would seek to elucidate all structures by arguing upon 

 the assumption that the habits which creatures were intended 

 to have, determined the precise nature of the organs they should 

 possess. 



In surveying the natural world, men are rarely, if ever, 

 justified in taking it for granted that the only possible mode 

 of accomplishing a result is that which they see adopted 

 in certain cases. They may be quite right in asserting that it 

 is the only mode consistent with particular conditions ; but 



* Lectures on the Elements of Comparative Anatomy, By Thomas Henry 

 Huxley, F.R.S., Professor of Natural History, Royal School of Mines ; and Pro- 

 fessor of Comparative Anatomy and Physiology to the Royal College of Surgeons, 

 England. On the Classification of Animals, and on the Vertebrate SAii/t. 

 Churchill and Sons. 



